1. Field of the Invention
The present invention relates to an antenna and more in particular, to an antenna for an electronic tag.
2. Related Art of the Invention
An electronic tag is widely applied in a variety of products or working pieces. After a signal emitted from a reading device is received by the antenna of the electronic tag or the reading device is close to the electronic tag, the signal is transmitted back to the reading device. Accordingly, the reading device can read the information of the electronic tag which is attached to the product or detect the position of the working piece.
FIG. 1 schematically shows a state in use of a conventional electronic tag. As shown in FIG. 1, a conventional electronic tag 100 has an antenna having a first polygonal metallic frame 101; a second polygonal metallic frame 102 surrounds and electrically connects to the first polygonal, metallic frame 101. Two radiation bodies 103 are respectively electrically connected to either side of the second polygonal metallic frame 102, and the radiation bodies 103 are laid out in the serpentine shape. A chip 104 is electrically connected to the first polygonal metallic frame 101 and the second polygonal metallic frame 102.
When the electronic tag 100 is used to be attached to a product 200, the electronic tag 100 has to keep a suitable distance away from a metallic surface 201 of the product 200 because the metallic surface 201 may affect the property of the antenna if the chip 104 of the electronic tag 100 is close to the metallic surface 201 too much. Specifically, in the event that the electronic tag 100 is close to the metallic surface 201 too much, the information of the electronic tag 100 cannot be read by the reading device within the designed reading scope since the signal reading distance of such electronic tag 100 is reduced thereby.